U.S. patent number 10,190,510 [Application Number 15/229,121] was granted by the patent office on 2019-01-29 for fuel storage apparatus.
This patent grant is currently assigned to HONDA MOTOR CO., LTD.. The grantee listed for this patent is HONDA MOTOR CO., LTD.. Invention is credited to Kengo Ishimitsu.
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United States Patent |
10,190,510 |
Ishimitsu |
January 29, 2019 |
Fuel storage apparatus
Abstract
A fuel storage apparatus includes a fuel tank, a heat exchanger,
a fuel pipe, and a medium pipe. The heat exchanger performs heat
exchange between fuel inside the fuel tank and a heat exchange
medium. The fuel pipe is provided inside the fuel tank and delivers
the fuel to the heat exchanger. The medium pipe is provided outside
the fuel tank and delivers the heat exchange medium to the heat
exchanger. The heat exchanger includes a first joint and a second
joint. The first joint is provided inside the fuel tank and is
connectable to the fuel pipe. The second joint is provided outside
the fuel tank and is connectable to the medium pipe.
Inventors: |
Ishimitsu; Kengo (Wako,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
HONDA MOTOR CO., LTD. |
Tokyo |
N/A |
JP |
|
|
Assignee: |
HONDA MOTOR CO., LTD. (Tokyo,
JP)
|
Family
ID: |
58097692 |
Appl.
No.: |
15/229,121 |
Filed: |
August 5, 2016 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20170058791 A1 |
Mar 2, 2017 |
|
Foreign Application Priority Data
|
|
|
|
|
Aug 28, 2015 [JP] |
|
|
2015-168649 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02D
19/0649 (20130101); F02M 37/0064 (20130101); F02M
31/16 (20130101); F02M 37/0088 (20130101); B01D
61/362 (20130101); F02D 19/0671 (20130101); F02M
37/0082 (20130101); F02M 31/20 (20130101); Y02T
10/30 (20130101); Y02T 10/36 (20130101); Y02T
10/12 (20130101); Y02T 10/126 (20130101) |
Current International
Class: |
F02D
19/06 (20060101); B01D 61/36 (20060101); F02M
31/16 (20060101); F02M 37/00 (20060101); F02M
31/20 (20060101) |
Field of
Search: |
;123/1A |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Dallo; Joseph
Assistant Examiner: Wang; Yi-Kai
Attorney, Agent or Firm: Mori & Ward, LLP
Claims
What is claimed is:
1. A fuel storage apparatus comprising: a fuel tank; a heat
exchanger that performs heat exchange between fuel inside the fuel
tank and a heat exchange medium; a fuel pipe that is provided
inside the fuel tank and that delivers the fuel to the heat
exchanger; and a medium pipe that is provided outside the fuel tank
and that delivers the heat exchange medium to the heat exchanger,
the heat exchanger comprising: a first joint provided inside the
fuel tank and connectable to the fuel pipe; and a second joint
provided outside the fuel tank and connectable to the medium
pipe.
2. The fuel storage apparatus according to claim 1, wherein the
fuel tank has an opening, and wherein the heat exchanger
constitutes at least part of a lid that closes the opening.
3. The fuel storage apparatus according to claim 2, wherein the
fuel tank has a first fuel tank having a first opening and a second
fuel tank provided inside the first fuel tank, and wherein the heat
exchanger constitutes at least part of the lid that closes the
first opening.
4. The fuel storage apparatus according to claim 3, wherein the
second fuel tank has a second opening that opposes the first
opening, and wherein the heat exchanger constitutes at least part
of the lid that closes both the first opening and the second
opening.
5. The fuel storage apparatus according to claim 4, wherein the
second opening is defined by an inner wall surface of a cylindrical
portion formed in the second fuel tank, and wherein the lid has a
middle cylindrical portion that fits the second opening and an
outer circumferential portion that is in contact with a
circumferential edge of the first opening on an outer surface of
the first fuel tank.
6. The fuel storage apparatus according to claim 5, wherein an
annularly shaped first sealing member surrounding the first opening
is provided between the outer circumferential portion and the outer
surface of the first fuel tank, and wherein an annularly shaped
second sealing member is provided between an outer surface of the
middle cylindrical portion and the inner wall surface.
7. The fuel storage apparatus according to claim 4, wherein the
first joint is provided at a portion facing an inner side of the
second fuel tank.
8. The fuel storage apparatus according to claim 4, wherein the
first fuel tank has a separation device provided thereinside, the
separation device separating second fuel from first fuel stored in
the first fuel tank, and wherein the second fuel is stored in the
second fuel tank.
9. The fuel storage apparatus according to claim 8, wherein the
heat exchanger heats the first fuel that is delivered from the
first fuel tank to the separation device.
10. The fuel storage apparatus according to claim 2, wherein a
temperature sensor that detects the temperature of the fuel flowing
through the first joint is provided at a portion of the heat
exchanger facing an inner side of the fuel tank.
11. A fuel storage apparatus comprising: a fuel tank; a heat
exchanger mounted to the fuel tank to perform heat exchange between
fuel provided inside the fuel tank and a heat exchange medium; a
fuel pipe provided inside the fuel tank and connected to the heat
exchanger to supply the fuel to the heat exchanger via the fuel
pipe; and a medium pipe provided outside the fuel tank and
connected to the heat exchanger to supply the heat exchange medium
to the heat exchanger via the medium pipe.
12. The fuel storage apparatus according to claim 11, wherein the
heat exchanger includes a fuel joint structure provided inside the
fuel tank and connected to the fuel pipe.
13. The fuel storage apparatus according to claim 11, wherein the
heat exchanger includes a medium joint structure provided outside
the fuel tank and connected to the medium pipe.
14. The fuel storage apparatus according to claim 11, wherein the
fuel tank has an opening, and wherein the heat exchanger is mounted
to the fuel tank to close the opening.
15. The fuel storage apparatus according to claim 11, wherein the
fuel tank includes a first fuel tank having a first opening, and a
second fuel tank provided inside the first fuel tank, and wherein
the heat exchanger is mounted to the fuel tank to close the first
opening.
16. The fuel storage apparatus according to claim 15, wherein the
second fuel tank has a second opening, and wherein the heat
exchanger is mounted to the fuel tank to close both the first
opening and the second opening.
17. The fuel storage apparatus according to claim 16, wherein the
first fuel tank includes a circumferential edge provided about the
first opening, wherein the second fuel tank includes a cylindrical
portion having an inner wall surface defining the second opening,
and wherein the heat exchanger includes a middle cylindrical
portion provided in the second opening, and an outer
circumferential portion extending radially outward from the middle
cylindrical portion to face the circumferential edge of the first
fuel tank.
18. The fuel storage apparatus according to claim 17, wherein a
first sealing member has an annular shape and is provided about the
first opening, the first sealing member being provided between the
outer circumferential portion and the circumferential edge of the
first fuel tank, and wherein a second sealing member has an annular
shape and is provided between a radially outer surface of the
middle cylindrical portion and the inner wall surface.
19. The fuel storage apparatus according to claim 12, wherein the
heat exchanger includes an inner end surface to face an inside of
the fuel tank, and wherein the fuel joint structure is provided on
the inner end surface.
20. The fuel storage apparatus according to claim 15, further
comprising: a separation device provided inside the first fuel tank
to separate second fuel from first fuel provided in the first fuel
tank, wherein the second fuel is stored in the second fuel
tank.
21. The fuel storage apparatus according to claim 20, wherein the
heat exchanger is mounted to the fuel tank to heat the first fuel
delivered from the first fuel tank to the separation device.
22. The fuel storage apparatus according to claim 12, further
comprising: a temperature sensor to detect a temperature of the
fuel flowing through the fuel joint structure, wherein the heat
exchanger includes an inner end surface to face an inside of the
fuel tank, and wherein the temperature sensor is provided on the
inner end surface.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. .sctn. 119
to Japanese Patent Application No. 2015-168649, filed Aug. 28,
2015, entitled "Fuel Storage Apparatus." The contents of this
application are incorporated herein by reference in their
entirety.
BACKGROUND
1. Field
The present disclosure relates to a fuel storage apparatus.
2. Description of the Related Art
There has been known a fuel storage system in which a separation
device is used to separate ethanol-blended gasoline or other raw
fuel containing components of different octane numbers into a
high-octane fuel containing more components of high octane numbers
than the raw fuel and a low-octane fuel containing more components
of low octane numbers than the raw fuel and in which the
high-octane fuel and the low-octane fuel are selectively supplied
to an internal combustion engine (see, for example, Japanese
Unexamined Patent Application Publication No. 2011-208541). Such a
fuel storage system includes a raw fuel tank that stores the raw
fuel, a separation device that separates the raw fuel into the
high-octane fuel and the low-octane fuel, and a high-octane fuel
tank that stores the high-octane fuel. The separation device
includes a heat exchanger (or heater) that heats the raw fuel, a
separator that uses a separation membrane to separate the heated
raw fuel into the high-octane fuel and the low-octane fuel in
accordance with the principle of pervaporation, and a cooler that
cools the fuels resulting from the separation process. When the
internal combustion engine runs, for example, at a high compression
ratio, the fuel storage system can prevent knocking of the engine
by increasing the ratio of the high-octane fuel to be supplied to
the engine.
SUMMARY
According to one aspect of the present invention, a fuel storage
apparatus includes a fuel tank, a heat exchanger, a fuel pipe, and
a medium pipe. The heat exchanger performs heat exchange between
fuel inside the fuel tank and a heat exchange medium. The fuel pipe
is provided inside the fuel tank and delivers the fuel to the heat
exchanger. The medium pipe is provided outside the fuel tank and
delivers the heat exchange medium to the heat exchanger. The heat
exchanger includes a first joint and a second joint. The first
joint is provided inside the fuel tank and is connectable to the
fuel pipe. The second joint is provided outside the fuel tank and
is connectable to the medium pipe.
According to another aspect of the present invention, a fuel
storage apparatus includes a fuel tank, a heat exchanger, a fuel
pipe, and a medium pipe. The heat exchanger is mounted to the fuel
tank to perform heat exchange between fuel provided inside the fuel
tank and a heat exchange medium. The fuel pipe is provided inside
the fuel tank and is connected to the heat exchanger to supply the
fuel to the heat exchanger via the fuel pipe. The medium pipe is
provided outside the fuel tank and is connected to the heat
exchanger to supply the heat exchange medium to the heat exchanger
via the medium pipe.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the
attendant advantages thereof will be readily obtained as the same
becomes better understood by reference to the following detailed
description when considered in connection with the accompanying
drawings.
FIG. 1 is a schematic diagram of a fuel storage apparatus according
to an embodiment.
FIG. 2 is a perspective view of a first lid as viewed obliquely
from below.
FIG. 3 is an enlarged sectional view of a first lid and its
surrounding components of a fuel storage apparatus.
DESCRIPTION OF THE EMBODIMENTS
The embodiments will now be described with reference to the
accompanying drawings, wherein like reference numerals designate
corresponding or identical elements throughout the various
drawings.
An embodiment of a fuel storage apparatus according to the present
application will be described below with reference to the attached
drawings. The fuel storage apparatus 1 according to the embodiment
is an apparatus that is mounted on a motor vehicle so as to supply
fuel to an internal combustion engine 100 mounted on the motor
vehicle. The fuel storage apparatus 1 separates a high-octane fuel
from a raw fuel supplied to the vehicle and stores the high-octane
fuel in such a manner as to be isolated from the raw fuel. The raw
fuel, after being subjected to the process of separating the
high-octane fuel, has a higher ratio of low-octane fuel. According
to conditions under which the motor vehicle travels, the fuel
storage apparatus 1 selectively delivers the high-octane fuel and
the raw fuel (containing the low-octane fuel) to the internal
combustion engine 100. The raw fuel is fuel of different octane
numbers and may include a mix of ethanol or other alcohol and
gasoline (for example, ethanol-blended gasoline). The high-octane
fuel contains a higher ratio of high-octane fuel than the raw fuel,
while the low-octane fuel contains a higher ratio of low-octane
fuel than the raw fuel. For the raw fuel consisting of
ethanol-blended gasoline, the high-octane fuel includes ethanol as
the major component, while the low-octane fuel includes gasoline
having a lower ratio of ethanol content (concentration).
As shown in FIG. 1, the fuel storage apparatus 1 includes a raw
fuel tank 2 (a first fuel tank) for storing the raw fuel. In this
embodiment, the raw fuel tank 2 is formed of resin. The raw fuel
tank 2 may be formed to have any shape. As shown in FIGS. 1 through
3, the raw fuel tank 2 includes a top wall 2A, a bottom wall 2B,
both of which oppose each other at a distance, and side walls 2C
that are provided so as to extend to circumferential edges of the
top wall 2A and the bottom wall 2B, all of which create a space
therein.
The top wall 2A has a first opening 4 (first opening) and a second
opening 5, both of which pass through the top wall 2A in the
thickness direction. The first opening 4 is openable and closable
by a first lid 7, while the second opening 5 is openable and
closable by a second lid 8. In addition, the top wall 2A has a
filler pipe 9 through which the raw fuel is supplied from the
outside.
The fuel storage apparatus 1 has in the raw fuel tank 2 a frame 11
as a skeleton member of the raw fuel tank 2, most parts of a
separation device 12 that separates the raw fuel into the
high-octane fuel and the low-octane fuel, and a high-octane fuel
tank 13 (second fuel tank) for storing the high-octane fuel
separated by the separation device 12. The high-octane fuel tank 13
has a third opening 14 (second opening) in the top wall 13A. As
detailed later, the third opening 14 is disposed so as to oppose
the first opening 4 and is closed by the first lid 7 together with
the first opening 4.
The separation device 12 includes as major components a separator
17, a condenser 18, a buffer tank 19, first through third heat
exchangers 21, 22, 23, a fuel circulation pump 25, and a vacuum
pump 26 (negative pressure pump). The separator 17 and the
condenser 18 are coupled to each other, thereby constituting a
separator unit 20. Of the components of the separation device 12,
the separator 17, the condenser 18, the buffer tank 19, the first
heat exchanger 21, the fuel circulation pump 25, and the vacuum
pump 26 are disposed inside the raw fuel tank 2 outside the
high-octane fuel tank 13, while the second heat exchanger 22 is
incorporated into the first lid 7 and the third heat exchanger 23
is disposed outside the raw fuel tank 2.
The fuel storage apparatus 1 has a raw fuel pump 28 provided inside
the raw fuel tank 2 outside the high-octane fuel tank 13, the raw
fuel pump 28 pressure-feeding to the internal combustion engine 100
the low-octane fuel (raw fuel) stored inside the raw fuel tank 2
outside the high-octane fuel tank 13. In addition, the fuel storage
apparatus 1 has a high-octane fuel pump 29 that pressure-feeds the
high-octane fuel stored inside the high-octane fuel tank 13 to the
internal combustion engine 100.
The frame 11 supports the raw fuel tank 2 from the inside, thereby
reducing or eliminating possible deformation of the raw fuel tank
2. The frame 11 is formed of, for example, resin. The frame 11
supports the high-octane fuel tank 13, the separation unit 20, the
buffer tank 19, the first heat exchanger 21, the fuel circulation
pump 25, and the vacuum pump 26.
The fuel circulation pump 25 feeds the raw fuel stored in the raw
fuel tank 2 to the separator 17 through the process of
pressurization of the raw fuel. The fuel circulation pump 25, the
condenser 18, the first heat exchanger 21, and the second heat
exchanger 22 are provided in this order on the path of a fuel pipe
31 that connects the fuel circulation pump 25 and the separator 17.
More specifically, the fuel pipe 31 includes a first section 31A
connecting the fuel circulation pump 25 and the condenser 18, a
second section 31B connecting the condenser 18 and the first heat
exchanger 21, and a third section 31C connecting the first heat
exchanger 21 and the second heat exchanger 22, and a fourth section
31D connecting the second heat exchanger 22 and the separator 17.
The third section 31C and the fourth section 31D have portions that
pass through walls of the high-octane fuel tank 13. The raw fuel
pressure-fed from the fuel circulation pump 25 is subjected to heat
exchange by the condenser 18, the first heat exchanger 21, and the
second heat exchanger 22 and, as a result, is supplied to the
separator 17 at an elevated temperature compared with the raw fuel
stored at the bottom of the raw fuel tank 2. The condenser 18, the
first heat exchanger 21, and the second heat exchanger 22 are
detailed later in this description.
The separator 17 separates the raw fuel into the high-octane fuel
and the low-octane fuel in accordance with the principle of
pervaporation. The separator 17 has a separation membrane 17A that
selectively allows the high-octane fuel of the raw fuel to pass
therethrough, a first chamber 17B, and a second chamber 17C both of
which are separated by the separation membrane 17A. The separation
membrane 17A includes, for example, a nonporous polymer membrane or
an inorganic membrane that is microporous at the molecular level
and is appropriately selected depending on the component to be
separated from the raw fuel. For example, if the raw fuel is
ethanol-blended gasoline, the separation membrane 17A may include a
membrane that selectively allows ethanol and aromatic components to
pass therethrough.
Pumped by the fuel circulation pump 25, the raw fuel passes through
the condenser 18, the first heat exchanger 21, and the second heat
exchanger 22. During the passage of the above units, the
temperature and pressure of the raw fuel are raised and the raw
fuel is delivered to the first chamber 17B of the separator 17. The
second chamber 17C is depressurized by the vacuum pump 26 to be
described later. This causes the high-octane fuel of the raw fuel
delivered to the first chamber 17B to turn into a gas that passes
through the separation membrane 17A and becomes trapped in the
second chamber 17C. As a result, the fuel trapped in the second
chamber 17C becomes the high-octane fuel that includes more of the
high-octane component than the raw fuel. In contrast, as
progressing toward an outlet side of the first chamber 17B, the raw
fuel delivered to the first chamber 17B is deprived of the
high-octane component, becoming low-octane fuel that includes more
low-octane fuel than the raw fuel. If the raw fuel is
ethanol-blended gasoline, the high-octane fuel trapped in the
second chamber 17C includes ethanol as a major component, while the
low-octane fuel passing through the first chamber 17B includes
gasoline having a lower ratio of ethanol content
(concentration).
It is preferable that the condenser 18 be disposed adjacent to the
second chamber 17C of the separator 17. The condenser 18 is coupled
to the lower part of the separator 17 in such a manner that the
separator 17 and the condenser 18 constitute the single separator
unit 20.
The condenser 18 performs heat exchange between the gaseous
high-octane fuel delivered from the second chamber 17C and the raw
fuel delivered from the fuel circulation pump 25. Through the
process of this heat exchange, the gaseous high-octane fuel is
cooled and condensed into a liquid state, while the raw fuel is
heated.
The condenser 18 is connected to the high-octane fuel tank 13 via
the fuel line 32. A buffer tank 19 is provided on the path of the
fuel line 32. The condenser 18 is disposed above the buffer tank 19
and the high-octane fuel tank 13, while the buffer tank 19 is
disposed above the high-octane fuel tank 13. More specifically, the
condenser 18, the buffer tank 19, and the high-octane fuel tank 13
are configured in terms of positional relationship so as to ensure
that a fluid level in the condenser 18 is positioned above a fluid
level in the buffer tank 19 and a fluid level in the high-octane
fuel tank 13 and that the fluid level in the buffer tank 19 is
positioned above the fluid level in the high-octane fuel tank 13.
In addition, it is preferable that the separator 17 be disposed
above the buffer tank 19 and the high-octane fuel tank 13. Such a
configured positional relationship of the condenser 18, the buffer
tank 19, and the high-octane fuel tank 13 enables the high-octane
fuel in a liquid state to flow from the condenser 18 into the
buffer tank 19 due to gravity. Then, the high-octane fuel flows
into the high-octane fuel tank 13.
A first one-way valve 34 that allows only the flow of a fluid from
the condenser 18 to the buffer tank 19 is provided on the fuel line
32 at a connection between the condenser 18 and the buffer tank 19.
In addition, a second one-way valve 35 that allows only the one-way
flow of a fluid from the buffer tank 19 to the high-octane fuel
tank 13 is provided on the fuel line 32 at a connection between the
buffer tank 19 and the high-octane fuel tank 13.
An inlet port of the vacuum pump 26 is connected to a gas-phase
section, namely an upper section, of the buffer tank 19 via a pipe
37. In addition, an outlet port of the vacuum pump 26 is connected
to a liquid-phase section (namely, a lower section) of the
high-octane fuel tank 13 via a pipe 38. When the vacuum pump 26 is
activated, the gas in the upper section of the buffer tank 19 is
delivered to the high-octane fuel tank 13 through the pipes 37, 38,
causing the buffer tank 19 to be depressurized. The depressurized
buffer tank 19 facilitates the flow of the fluid from the condenser
18 to the buffer tank 19. As a result, the first one-way valve 34
is opened, resulting in depressurization of the condenser 18 and
the second chamber 17C of the separator 17, both of which are in
communication with the buffer tank 19. At this time, since the
buffer tank 19 is depressurized, the second one-way valve 35 is
closed and, as a result, the high-octane fuel tank 13 is not
depressurized. When the vacuum pump 26 is deactivated, the pressure
inside the buffer tank 19 and the condenser 18 becomes equal to the
pressure inside the raw fuel tank 2, allowing the high-octane fuel
in the buffer tank 19 to flow into the high-octane fuel tank 13
through the second one-way valve 35 due to gravity.
The high-octane fuel tank 13 has an upward extending communication
pipe 39 provided in the top wall 13A thereof, the communication
pipe 39 providing communication between the gas-phase section of
the upper section of the high-octane fuel tank 13 and the gas-phase
section of the upper section of the raw fuel tank 2. An upper end
of the communication pipe 39 is disposed close to an inner surface
of the top wall 2A of the raw fuel tank 2.
An outlet port of the first chamber 17B of the separator 17 is in
communication with a lower section of an internal space of the raw
fuel tank 2 via the fuel line 41. The separator 17, the first heat
exchanger 21, the third heat exchanger 23, a strainer 42, and a
pressure-regulating valve 43 are provided in this order on the path
of the fuel line 41. More specifically, the fuel line 41 includes a
fifth section 41A connecting the outlet port of the first chamber
17B of the separator 17 and the first heat exchanger 21, a sixth
section 41B connecting the first heat exchanger 21 and the third
heat exchanger 23, a seventh section 41C connecting the third heat
exchanger 23 and the strainer 42, and an eighth section 41D
connecting the strainer 42 and the pressure-regulating valve
43.
The first heat exchanger 21 performs heat exchange between the
relatively low-temperature raw fuel delivered to the separator 17
from the fuel circulation pump 25 and the relatively
high-temperature low-octane fuel passing through the separator 17.
The heat exchanger 21 may include a publicly known countercurrent
exchanger. Through the process of heat exchange occurring in the
first heat exchanger 21, the raw fuel delivered to the separator 17
from the fuel circulation pump 25 is heated, while the low-octane
fuel passing through the separator 17 is cooled.
The third heat exchanger 23 is provided outside the raw fuel tank
2. The fuel line 41 extends from the first heat exchanger 21 to the
third heat exchanger 23 through the second lid 8. In addition, the
fuel line 41 extends from the third heat exchanger 23 to the inside
of the raw fuel tank 2 again through the second lid 8. In this
embodiment, the third heat exchanger 23 includes an air-cooled
cooler (or a radiator) that performs heat exchange between fuel and
air. The relatively high-temperature low-octane fuel passing
through the separator 17 is cooled by the third heat exchanger 23.
In another embodiment, the third heat exchanger 23 may be provided
inside the raw fuel tank 2. For example, the third heat exchanger
23 may be provided on the bottom wall 2B of the raw fuel tank 2 so
as to allow heat exchange between the relatively high-temperature
low-octane fuel passing through the separator 17 and the bottom
wall 2B. The bottom wall 2B of the raw fuel tank 2 is cooled by air
cooling that occurs when the vehicle provided with the fuel storage
apparatus 1 is travelling or by forced air generated by a fan or
the like.
The low-octane fuel passing through the third heat exchanger 23
enters the strainer 42 where foreign matter is removed. Then, after
passing through the pressure-regulating valve 43, the low-octane
fuel is discharged to the bottom of the raw fuel tank 2 and mixed
into the raw fuel. The low-octane fuel mixed into the raw fuel
degrades the octane number of the fuel of the raw fuel tank 2 as a
whole. As the process of the separation progresses (namely, as the
total amount of raw fuel passing through the separator 17
increases), the fuel of the raw fuel tank 2 continues to degrade in
octane number, more closely resembling the low-octane fuel in
component composition. The pressure-regulating valve 43 regulates
pressure of the raw fuel and the low-octane fuel contained in the
path from the fuel circulation pump 25 to the pressure-regulating
valve 43, thereby maintaining pressure of the raw fuel of the first
chamber 17B of the separator 17 at a predetermined level. More
specifically, when the pressure of the raw fuel (or the low-octane
fuel) is raised by the fuel circulation pump 25 to such a degree
that a predetermined level is exceeded, the pressure-regulating
valve 43 discharges the raw fuel (or the low-octane fuel) to the
raw fuel tank 2, thereby maintaining the pressure at a
predetermined level.
The second heat exchanger 22 is used as a heater for heating the
raw fuel, performing heat exchange between the raw fuel that is
pressure-fed to the separator 17 from the fuel circulation pump 25
and a high-temperature heating medium delivered from outside the
raw fuel tank 2. The second heat exchanger 22 includes, for
example, a publicly known heat exchanger. The high-temperature
heating medium delivered to the second heat exchanger 22 includes,
for example, engine coolant whose temperature is raised through the
process of passing through the internal combustion engine 100, a
lubricating oil whose temperature is raised through the process of
passing through the internal combustion engine 100, an automatic
transmission fluid whose temperature is raised through the process
of passing through a transmission, a fluid whose temperature is
raised through the process of heat exchange with exhaust gas
emitted from the internal combustion engine 100, and exhaust gas.
The high-temperature heating medium used in this embodiment
includes engine coolant heated by the internal combustion engine
100 and is delivered to the second heat exchanger 22 through medium
pipes 103A, 103B that are in communication with a coolant passage
102 of the internal combustion engine 100.
The second heat exchanger 22, together with a lid member 50,
constitutes the first lid 7. In other words, the second heat
exchanger 22 constitutes at least part of the first lid 7.
As shown in FIGS. 2 and 3, the second heat exchanger 22 includes a
cylindrically-shaped main body 60 that constitutes an internal
space thereof, a fuel inlet pipe 61 projecting from the main body
60, a fuel outlet passage member 62, a medium inlet pipe 63, a
medium outlet pipe 64, a fuel passage 65 that is disposed in the
internal space of the main body 60 and that is connected to the
fuel inlet pipe 61 and the fuel outlet passage member 62, and a
temperature sensor 67.
The main body 60 includes a cylindrically-shaped circumferential
wall 60A, an outer end wall 60B that closes one end of the
circumferential wall 60A, and an inner end wall 60C that closes the
other end of the circumferential wall 60A. The inner end wall 60C
is larger in diameter than the circumferential wall 60A. The fuel
passage 65 includes a plurality of plate-like branch passages that
are spaced in parallel apart from one another, an inlet port that
connects ends of the branch passages to one another, and an outlet
port that connects the other ends of the branch passages to one
another. Each of the branch passages is formed by joining, for
example, circumferential edges of two metal plates opposing each
other, while inlet and outlet ports are formed of, for example,
pipes. The inlet and outlet of the fuel passage 65 pass through the
inner end wall 60C and are opened to the outside of the inner end
wall 60C.
An end of the fuel inlet pipe 61 is joined to an external surface
of the inner end wall 60C so as to be connected to the inlet port
of the fuel passage 65. In addition, the fuel outlet passage member
62 is joined to the external surface of the inner end wall 60C so
as to be connected to the outlet port of the fuel passage 65. The
fuel outlet passage member 62 includes a base 62A joined to the
inner end wall 60C and an end portion 62B of a pipe member joined
to the base 62A. The base 62A and the end portion 62B have a
passage formed thereinside through which the fuel flows. The
temperature sensor 67 is joined to the base 62A and has its sensing
element provided in the passage of the base 62A. The temperature
sensor 67 detects the temperature of the fuel flowing in the base
62A.
The fuel inlet pipe 61 has a joint 61A (first joint of a fuel joint
structure) provided at an end thereof, while the fuel outlet
passage member 62 has a joint 62C (first joint of the fuel joint
structure) provided at an end 62B thereof. The joint 61A is formed
so as to be connected to an end of the third section 31C of the
fuel pipe 31, while the joint 620 is formed so as to be connected
to an end of the fourth section 31D of the fuel pipe 31. The joint
61A provides connection between the third section 31C of the fuel
pipe 31 and the fuel inlet pipe 61, while the joint 62C provides
connection between the fuel outlet passage member 62 and the fourth
section 31D of the fuel pipe 31. With this arrangement, the fuel
flowing through the third section 31C of the fuel pipe 31 passes
through the fuel inlet pipe 61, the fuel passage 65, and the fuel
outlet passage member 62, in this order, into the fourth section
31D.
Ends (base ends) of the medium inlet pipe 63 and the medium outlet
pipe 64 are joined to the circumferential wall 60A so as to be
connected to the internal space of the main body 60. The medium
inlet pipe 63 and the medium outlet pipe 64 have joints 63A, 64A
(second joints of a medium joint structure) provided at another
ends (or tips) thereof. The joint 63A is formed so as to be
connected to an end of the medium pipe 103A, while the joint 64A is
formed so as to be connected to an end of the medium pipe 103B. The
joint 63A provides connection between the medium pipe 103A and the
medium inlet pipe 63, while the joint 64A provides connection
between the medium outlet pipe 64 and the medium pipe 103B. With
this arrangement, the coolant (namely, heat exchange medium) that
flows through the coolant passage 102 and that is heated through
the process of heat exchange with the internal combustion engine
100 passes through the medium pipe 103A, the medium inlet pipe 63,
the internal space of the main body 60, the medium outlet pipe 64,
and the medium pipe 103B, in this order, and is finally returned to
the coolant passage 102. The coolant flowing through the internal
space of the main body 60 performs heat exchange with the fuel
flowing through the fuel passage 65. As a result, the fuel flowing
through the fuel passage 65 is heated, while the coolant flowing
through the internal space of the main body 60 is cooled.
The lid member 50 includes a first cylindrical portion 51 (central
cylindrical portion), a second cylindrical portion 52, both of
which are provided at the center thereof, and a flange 53 provided
at an outer circumferential portion thereof. The first cylindrical
portion 51 includes a cylindrically-shaped first circumferential
wall 51A and a first bottom wall 51B provided at an axial end of
the first circumferential wall 51A with the other end being opened.
The first bottom wall 51B has a circular through-hole 51C passing
therethrough in the thickness direction at the center thereof. The
second cylindrical portion 52 includes a cylindrically-shaped
second circumferential wall 52A that is larger in diameter than the
first circumferential wall 51A and a second bottom wall 52B
provided at an axial end of the second circumferential wall 52A
with the other end being opened. The second bottom wall 52B has a
circular through-hole passing therethrough in the thickness
direction at the center thereof, the through-hole being joined to
the other end of the first circumferential wall 51A. The flange 53
is formed in an annular shape, projecting radially outward from the
other end of the second circumferential wall 52A. In other words,
the lid member 50 has the second cylindrical portion 52 projecting
from the flange 53 to one side and the first cylindrical portion 51
further projecting to one side from the second bottom wall 52B of
the second cylindrical portion 52.
The inner end wall 60C of the main body 60 of the second heat
exchanger 22 is joined to a surface of the first bottom wall 51B on
the side of the first circumferential wall 51A and closes the
through-hole 51C. The fuel inlet pipe 61 and the fuel outlet
passage member 62 pass through the through-hole 51C and projects to
the side across the first circumferential wall 51A from the first
bottom wall 51B.
As shown in FIG. 3, a first boss 71 projecting upward from the top
wall 2A is formed around the first opening 4. The first boss 71 has
a male thread 71A formed in an outer circumferential surface
thereof. An annularly shaped inward-facing flange 71B projecting
radially inward is formed at a projecting end of the first boss 71.
The inward-facing flange 71B expands a projecting end surface of
the first boss 71. The first opening 4 is formed as an inner hole
provided on the inner side of the inward-facing flange 71B. The
upper end surface of the inward-facing flange 71B is a plane that
is perpendicular to the axis line of the first opening 4 (first
boss 71). An annularly shaped first sealing member 72 extending so
as to surround the first opening 4 is disposed on the upper end
surface of the inward-facing flange 71B. The first sealing member
72 is flexible and can adhere to a surface to be sealed.
The third opening 14 is disposed inside the raw fuel tank 2 so as
to be substantially coaxial with the first opening 4. A
cylindrically-shaped third boss 76 upward projecting from the top
wall 13A of the high-octane fuel tank 13 is formed around the third
opening 14. The third opening 14 is formed as an inner hole of the
third boss 76. The third opening 14 is configured to be smaller in
diameter than the first opening 4. A projection 77 projecting
upward and being in contact with the back side of the top wall 2A
of the raw fuel tank 2 is formed on the upper surface of the top
wall 13A. The projecting end (upper end) of the third boss 76 is
disposed in the raw fuel tank 2 so as to be located downward away
from the inward-facing flange 71B of the first boss 71.
The flange 53 of the lid member 50 is in contact with the
inward-facing flange 71B of the first boss 71 with the first
sealing member 72 therebetween. With this arrangement, the first
opening 4 is closed by the first lid 7. When the flange 53 comes
into contact with the inward-facing flange 71B of the first boss 71
with the first sealing member 72 therebetween, the second
cylindrical portion 52 loosely fits into the first opening 4 and
the first cylindrical portion 51 fits into the third opening 14
(inner hole of the third boss 76). An annularly shaped sealing
groove 51D extending circumferentially is provided in the
circumferential surface of the first circumferential wall 51A. The
sealing groove 51D has an annularly shaped second sealing member 54
mounted therein. The second sealing member 54 is flexible. The
second sealing member 54 provides a seal between the inner
circumferential surface of the third boss 76 and the outer
circumferential surface of the first circumferential wall 51A. With
this arrangement, the third opening 14 is closed by the first lid
7. As described above, the first lid 7 closes both the first
opening 4 and the third opening 14.
The flange 53 is fastened to the first boss 71 by means of a first
cap 73 screwed up to the male thread 71A of the first boss 71. The
first cap 73 includes a cylindrical portion 73A that can accept the
first boss 71, a female thread 73B that is formed in an inner
surface of the cylindrical portion 73A and into which the male
thread 71 of the first boss 71 is screwed, and a flange 73C
projecting radially inward from one end of the cylindrical portion
73A. With the first cap 73 screwed up to the first boss 71, the
flange 53 is pressed against the first boss 71 by the flange 73C of
the first cap 73, thereby adhering closely to the inward-facing
flange 71B of the first boss 71 with the first sealing member 72
therebetween.
With the first opening 4 and the third opening 14 being closed by
the first lid 7, the joints 61A, 62C connected to the fuel pipe 31
are disposed inside the high-octane fuel tank 13, while the joints
63A, 64A connected to the medium pipes 103A, 103B are disposed
outside the raw fuel tank 2.
As shown in FIG. 1, a cylindrically-shaped second boss 81
projecting upward from the top wall 2A is formed around the second
opening 5. The second opening 5 is formed as an inner hole of the
second boss 81. The second boss 81 has a male thread (not
illustrated) formed in an outer circumferential surface thereof.
The second lid 8 is formed in the shape of a disk and can come into
contact with a projecting end surface of the second boss 81 with a
sealing member (not illustrated) therebetween. The second lid 8 is
fastened to the second boss 81 by means of a second cap 82 screwed
up to the second boss 81. The second cap 82 includes a cylindrical
portion that can accept the second boss 81, a female thread that is
formed in an inner surface of the cylindrical portion and into
which the male thread of the second boss 81 is screwed, and a
flange projecting radially inward from one end of the cylindrical
portion. With the second cap 82 screwed up to the second boss 81,
the second lid 8 is pressed against the second boss 81 by the
flange of the second cap 82, thereby adhering closely to a
projecting end surface of the second boss 81 with the sealing
member therebetween and closing the second opening 5.
A first fuel line 112 connecting a raw fuel pump 28 and a first
injector 111 of the internal combustion engine 100, a second fuel
line 114 connecting a high-octane fuel pump 29 and a second
injector 113 of the internal combustion engine 100, a breather pipe
115 connecting the gas-phase section of the upper section of the
raw fuel tank 2 and an upstream end of the filler pipe 9, a vapor
pipe 117 connecting the gas-phase section of the upper section of
the raw fuel tank 2 and a canister 116, and the sixth section 41B
and the seventh section 41C of the fuel line 41 pass through the
second lid 8. In addition, a bundle of cables including signal
lines and power cables for the fuel circulation pump 25, the vacuum
pump 26, the raw fuel pump 28, and the high-octane fuel pump 29
pass through the second lid 8, though not illustrated. A portion of
the second lid 8 through which the first fuel line 112, the second
fuel line 114, the breather pipe 115, the vapor pipe 117, and the
sixth section 41B and the seventh section 41C of the fuel line 41
pass is sealed so as to be airtight.
When the vehicle is filled up with fuel through the filler pipe 9,
the breather pipe 115 enables gaseous matter inside the raw fuel
tank 2 to be released to the filler pipe 9 therethrough, thereby
facilitating a flow of raw fuel into the raw fuel tank 2. In
addition, the vapor pipe 117 enables fuel vapor inside the raw fuel
tank 2 to be released to the canister 116 therethrough, thereby
maintaining the pressure inside the raw fuel tank 2 at the
atmospheric pressure. The fuel vapor sent to the canister 116 are
adsorbed onto activated carbon contained in the canister 116.
Negative pressure generated in an air intake passage 120 during
operation of the internal combustion engine 100 is used to suck the
fuel adsorbed onto the activated carbon of the canister 116 into
combustion chambers of the engine where the fuel is combusted. The
vapor pipe 117 has a float valve 122 provided at an end thereof
that is located inside the raw fuel tank 2. The float valve 122 is
opened or closed according to the level of the raw fuel inside the
raw fuel tank 2, thereby preventing liquid fuel from flowing into
the vapor pipe 117.
A strainer 123 for removing impurities from the fuel is provided in
the second fuel line 114 at a point located inside the high-octane
fuel tank 13.
Operation and effects of the fuel storage apparatus 1 will be
described below. Pressurized by the fuel circulation pump 25, the
raw fuel of the raw fuel tank 2 passes through the condenser 18,
the first heat exchanger 21, and the second heat exchanger 22, in
this order, into the first chamber 17B of the separator 17. At this
time, the temperature of the raw fuel is raised through the
processes of heat exchange occurring in the condenser 18 with the
gas of the high-temperature high-octane fuel, heat exchange in the
first heat exchanger 21 with the high-temperature low-octane fuel
passing through the separator 17, and heat exchange in the second
heat exchanger 22 with heated engine coolant.
When the vacuum pump 26 is activated, the second chamber 17C of the
separator 17 is depressurized. In the separator 17, when the second
chamber 17C is depressurized by means of suction by the vacuum pump
26, the high-octane fuel component of the
high-temperature/high-pressure raw fuel delivered to the first
chamber 17B turns into a gas that passes through the separation
membrane 17A and becomes trapped in the second chamber 17C. The
gaseous high-octane fuel trapped in the second chamber 17C flows
into the condenser 18 where the gaseous fuel is cooled and
condensed through the process of heat exchange with the raw fuel
delivered to the separator 17 by the fuel circulation pump 25. The
high-octane fuel condensed in the condenser 18 flows into the
buffer tank 19 for storage due to gravity.
When the vacuum pump 26 is deactivated, the pressure inside the
buffer tank 19 becomes equal to the pressure inside the raw fuel
tank 2. Due to gravity, the high-octane fuel in the buffer tank 19
opens the second one-way valve 35 through which the high-octane
fuel flows into the high-octane fuel tank 13 where the high-octane
fuel is stored.
The low-octane fuel passing through the first chamber 17B of the
separator 17 is cooled through the process of heat exchange in the
first heat exchanger 21 with the raw fuel delivered to the
separator 17 by the fuel circulation pump 25 and is further cooled
in the heat exchanger 23. After that, the low-octane fuel passes
through the strainer 42 and the pressure-regulating valve 43 into
the raw fuel tank 2 where the low-octane fuel is mixed into the raw
fuel.
In the fuel storage apparatus 1, as the total amount of raw fuel
passing through the separator 17 increases, the amount of
high-octane fuel to be stored in the high-octane fuel tank 13
increases and, in addition, the ratio of the low-octane fuel
contained in the raw fuel increases. The amount of raw fuel passing
through the separator 17 can be regulated by controlling the fuel
circulation pump 25 and the vacuum pump 26. The fuel circulation
pump 25 and the vacuum pump 26 may be controlled by a fuel level of
the high-octane fuel tank 13, the concentration of the high-octane
fuel contained in the raw fuel, the operation hours of the fuel
circulation pump 25 or the like.
The fuel storage apparatus 1 according to this embodiment has the
separation device 12 and the high-octane fuel tank 13 disposed
inside the raw fuel tank 2. The raw fuel tank 2 configured to be
airtight eliminates the need for making airtight the separation
device 12, the high-octane fuel tank 13, and joints for connecting
these components, which provides an advantage of a smaller number
of airtight members or components required.
The third section 31C and the fourth section 31D of the fuel pipe
31 and the joints 61A, 62C connected to these sections are disposed
inside the high-octane fuel tank 13. For this reason, even if fuel
leaks from connections between the joints 61A, 62C and the third
section 31C and the fourth section 31D, the fuel remains in the
high-octane fuel tank 13 without escaping from the raw fuel tank 2
to the outside. In addition, the joints 63A, 64A connected to the
medium pipes 103A, 103B through which engine coolant flows are
disposed outside the raw fuel tank 2. For this reason, even if
engine coolant leaks from connections between the joints 63A, 64A
and the medium pipes 103A, 103B, engine coolant does not enter the
raw fuel tank 2 nor is mixed into the fuel.
The second heat exchanger 22 is incorporated into the first lid 7
providing a partition that is between the inside and outside of the
raw fuel tank 2 and between the inside and outside of the
high-octane fuel tank 13, which enables the joints 61A, 62C to be
easily disposed inside the high-octane fuel tank 13 (or raw fuel
tank 2) and also enables the joints 63A, 64A to be easily disposed
outside the raw fuel tank 2.
Both the first opening 4 and the third opening 14 are opened/closed
by the first lid 7, which allows the high-octane fuel tank 13 to be
easily opened/closed. In this embodiment, the direction in which
the first sealing member 72 between the first lid 7 and the first
boss 71 is compressed is different from the direction in which the
second sealing member 54 between the first lid 7 and the third boss
76 is compressed. For this reason, even if there is an error in the
relative position between the first opening 4 and the third opening
14, the first sealing member 72 provides a reliable and durable
seal between the first lid 7 and the first boss 71, while the
second sealing member 54 also provides a reliable and durable seal
between the first lid 7 and the third boss 76.
The present application is typically described with reference to,
but not limited to, the foregoing embodiment. Various modifications
are conceivable within the scope of the present application. For
example, although the second heat exchanger 22 is incorporated into
the first lid 7 that closes both the first opening 4 and the third
opening 14, the second heat exchanger 22 may be incorporated into a
lid that closes only an opening formed in the raw fuel tank 2, like
the second lid 8 that closes the second opening 5.
A first aspect of the present application provides a fuel storage
apparatus (1) that includes a fuel tank (2), a heat exchanger (22)
that performs heat exchange between fuel inside the fuel tank and a
heat exchange medium, a fuel pipe (31C, 31D) that is provided
inside the fuel tank and that delivers the fuel to the heat
exchanger, a medium pipe (103A, 103B) that is provided outside the
fuel tank and that delivers the heat exchange medium to the heat
exchanger, in which the heat exchanger has a first joint (61A, 62C)
provided inside the fuel tank and connectable to the fuel pipe and
a second joint (63A, 64A) provided outside the fuel tank and
connectable to the medium pipe.
With this arrangement, even if fuel leaks from connections between
the first joint and the fuel pipe, the fuel remains in the fuel
tank without escaping to the outside of the fuel tank. Likewise,
even if heat exchange medium leaks from connections between the
second joint and the medium pipe, the heat exchange medium does not
enter the fuel tank nor is mixed into the fuel.
A second aspect of the present application provides the fuel
storage apparatus in which the fuel tank may have an opening (4)
and the heat exchanger may constitute at least part of a lid (7)
that closes the opening.
The heat exchanger is incorporated into the lid providing a
partition between the inside and outside of the fuel tank, which
enables the first joints to be easily disposed inside the fuel tank
and also enables the second joints to be easily disposed outside
the fuel tank.
A third aspect of the present application provides the fuel storage
apparatus in which the fuel tank may have a first fuel tank (2)
having a first opening (4) and a second fuel tank (13) provided
inside the first fuel tank and in which the heat exchanger may
constitute at least part of the lid that closes the first
opening.
The heat exchanger is provided in the first fuel tank disposed
outside the second fuel tank, which enables easy installation of
the heat exchanger.
A fourth aspect of the present application provides the fuel
storage apparatus in which the second fuel tank may have a second
opening (14) that opposes the first opening and in which the heat
exchanger may constitute at least part of the lid that closes both
the first opening and the second opening.
The lid including the heat exchanger closes both the first opening
and the second opening, which results in a reduction in the number
of parts and components required.
A fifth aspect of the present application provides the fuel storage
apparatus in which the second opening may be defined by an inner
circumferential surface of a cylindrical portion formed in the
second fuel tank and in which the lid may have a middle cylindrical
portion (51) that fits the second opening and an outer
circumferential portion (53) that is in contact with a
circumferential edge of the first opening on an outer surface of
the first fuel tank.
With this arrangement, even if there is a dimensional error in the
relative position between the first opening and the second opening,
the lid can reliably close the first opening and the second
opening, making the dimensional error allowable.
A sixth aspect of the present application provides the fuel storage
apparatus in which an annularly shaped first sealing member (72)
surrounding the first opening may be provided between the outer
circumferential portion and the outer surface of the first fuel
tank and in which an annularly shaped second sealing member (54)
may be provided between an outer surface of the middle cylindrical
portion and the inner circumferential surface.
With this arrangement, the direction in which the first sealing
member is compressed is different from the direction in which the
second sealing member is compressed. For this reason, even if there
is an error in the relative position between the first opening and
the second opening, the first sealing member and the second sealing
member can reliably seal a gap between the lid and the
circumferential edge of the first opening and a gap between the lid
and the circumferential edge of the second opening.
A seventh aspect of the present application provides the fuel
storage apparatus in which the first joints may be provided at a
portion (60C) facing an inner side of the second fuel tank.
With this arrangement, if fuel leaks from connections between the
first joint and the fuel pipe, leaked fuel is trapped in the second
fuel tank.
An eighth aspect of the present application provides the fuel
storage apparatus in which the first fuel tank may have a
separation device (17) provided thereinside, the separation device
separating second fuel from first fuel stored in the first fuel
tank and in which the second fuel may be stored in the second fuel
tank.
With this arrangement, the separation device is disposed inside the
first fuel tank. For this reason, even if fuel leaks from the
separation device, from the pipe through which the fuel is
delivered to the separation device, or from the pipe through which
the fuel is delivered from the separation device to the second fuel
tank, the fuel remains in the first fuel tank.
A ninth aspect of the present application provides the fuel storage
apparatus in which a temperature sensor (67) that detects the
temperature of the fuel flowing through the first joints is
provided at a portion of the heat exchanger facing an inner side of
the fuel tank.
The temperature sensor is provided in the heat exchanger
constituting part of the lid that is detachable from the fuel tank,
which allows easy maintenance of the temperature sensor.
Obviously, numerous modifications and variations of the present
invention are possible in light of the above teachings. It is
therefore to be understood that within the scope of the appended
claims, the invention may be practiced otherwise than as
specifically described herein.
* * * * *